Deoxidizing agent and preparation method thereof

Abstract

The invention relates to the technical field of gas deoxidation, and particularly discloses a deoxidizer and a preparation method thereof. The preparation method of the deoxidizing agent comprises the following steps: S1, dissolving lanthanum salt, manganese salt and nickel salt in water, adding citric acid, adjusting the pH value, heating and mixing, spray-drying, heating and preserving heat, switching a mixed gas of O2 and N2, and heating and sintering to obtain particles A; s2, cerium salt, manganese salt and nickel salt are dissolved in water, citric acid is added, pH is adjusted, heating mixing, spray drying and heating sintering are conducted, and particles B are obtained; and S3, mixing the particles A and the particles B, grinding for 4-5 hours, adding a dispersing agent and water, uniformly mixing, adding a magnesium modified ceramsite carrier, carrying out vacuum impregnation for 45-55 minutes, carrying out solid-liquid separation, drying, carrying out heat preservation for 110-150 minutes in a mixed gas of H2 and N2 at 480-520 DEG C, and cooling to obtain the deoxidizer. The deoxidizing agent provided by the invention has excellent deoxidizing capacity.

Description

Technical Field

[0001] The present application relates to the technical field of gas deoxidation, and more specifically, to a deoxidizer and a preparation method thereof. Background Art

[0002] Currently, commonly used gas purification deoxidizers are categorized by their deoxidation mechanism into catalytic hydrogenation deoxidizers and chemical absorption deoxidizers. Catalytic hydrogenation deoxidizers, in the presence of hydrogen, remove oxygen by reacting residual oxygen in the feed gas with hydrogen over the action of a catalyst to produce water. These deoxidizers typically use precious metals such as Pd and Pt as active components, with carriers such as Al2O3, TiO2, and SiO2. They offer high deoxidation precision and mild reaction conditions, typically removing oxygen from the gas to very low levels at room temperature. However, they are expensive. Furthermore, since hydrogen must be present during use, these catalysts are currently primarily used for electrolytic hydrogen deoxidation to produce high-purity hydrogen and inert gases. Chemical absorption deoxidizers, typically using metals such as copper and manganese as active components, react chemically with oxygen to form oxides, thereby removing oxygen. However, these deoxidizers suffer from poor deoxidation performance, particularly in terms of precision and capacity.

[0003] Patent application document with publication number CN1342516A discloses a deoxidizer with MnO and CuO as active components. The specific preparation method is as follows (taking the preparation of Example 3 as an example): take 80 grams of MnCO3 and 10 grams of Al2O3, mix them thoroughly and crush them to above 500 mesh, add an appropriate amount of 10% dilute nitric acid, process them into strips, and dry them naturally; impregnate 10 grams of Cu(NO3)2 according to the weight ratio, roast them at 300°C under ventilation conditions for 6 hours, and cool them naturally to room temperature for use.

[0004] In this technical solution, MnCO3 and Al2O3 are directly physically mixed and crushed. The MnO generated by MCO3 is prone to agglomeration due to uneven mixing, resulting in a reduction in specific surface area and insufficient effective contact sites with oxygen. Although the Cu(NO3)2 impregnation can penetrate into the interior of the carrier through capillaries, the uneven pore structure of the carrier leads to uneven distribution of CuO, which ultimately results in a small deoxidation capacity. Summary of the Invention

[0005] In order to improve the deoxidation capacity, the present application provides a deoxidizer and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing a deoxidizer, which adopts the following technical solution: A method for preparing a deoxidizer comprises the following steps: S1: Dissolve lanthanum salt, manganese salt, and nickel salt in a molar ratio of 1:x:(1-x) in water, add citric acid, adjust the pH to 5.5-6.0, heat to 75-85°C, mix for 90-120 minutes, spray dry, first heat at 280-320°C, keep warm for 50-70 minutes, switch to a mixture of O2 and N2, and sinter at 720-760°C for 3-3.5 hours to obtain particles A; S2: Dissolve cerium salt, manganese salt, and nickel salt in a molar ratio of 1:(0.04-0.06):(0.04-0.05) in water, add citric acid, adjust the pH to 5.5-6.0, heat to 75-85°C, mix for 90-120 minutes, spray dry, and sinter at 580-620°C for 3-3.5 hours to obtain particles B; S3: Mix particles A and B, grind for 4-5 hours, add dispersant and water, mix evenly, add magnesium-modified ceramsite carrier, vacuum impregnate for 45-55 minutes, separate the solid and liquid, dry, keep warm at 480-520°C for 110-150 minutes under a mixture of H2 and N2, cool, and obtain a deoxidizer.

[0007] In this scheme, particle A is based on a specific ratio of La:Mn:Ni, and forms a stable metal-citric acid complex through pH control. It is spray-dried to lock the dispersion. After pre-decomposition, oxygen is precisely controlled by a specific ratio of oxygen and nitrogen mixed gas, and directional crystallization is formed at an appropriate temperature to form a main perovskite phase, ensuring an efficient oxygen migration channel; particle B maintains the stability of the fluorite phase CeO2 structure by limiting the Mn / Ni doping amount (≤10%), ensuring that its lattice oxygen has moderate activity. After mixing and grinding particles A and B, and then loading them on a magnesium-modified ceramsite carrier by vacuum impregnation, Ce on the surface of particle B is reduced in a H2 and N2 reducing atmosphere. 4+ Prioritize reduction to Ce 3+ , generating high-concentration oxygen vacancies, and the released electrons are transferred to particle A through the interface, triggering the migration of oxygen ions from the perovskite phase to CeO2, forming a continuous oxygen vacancy gradient, driving cyclic deoxidation, and effectively improving the deoxidation rate and capacity.

[0008] Preferably, in step S1, the value range of x is 0.5~0.8.

[0009] Preferably, in step S1, in the mixed gas of O2 and N2, the volume ratio of O2 to N2 is (15-20): (80-85).

[0010] Preferably, in step S3, in the mixture of H2 and N2, the volume ratio of H2 to N2 is (5-10): (90-95).

[0011] Preferably, in step S3, the dispersant is polyvinyl pyrrolidone.

[0012] Preferably, in step S3, the amount of the dispersant used is 1.5% to 2.5% of the total mass of particles A and particles B.

[0013] Preferably, in step S3, the mass ratio of particles A to particles B is (3-4):3.

[0014] Preferably, in step S3, the ratio of the mass of the magnesium-modified ceramsite to the total mass of particles A, particles B and water is (1.5-2.5):1.

[0015] Preferably, the preparation method of the magnesium-modified ceramsite carrier comprises the following steps: The kaolin, pore-forming agent and magnesium-modified molecular sieve are added into a reactor, water is added and kneaded evenly, extruded, granulated and dried, first sintered at 550-600°C for 1.5-2h, switched to an inert atmosphere, continued to heat up to 1100-1150°C, sintered for 2.5-3h, cooled, immersed in nitric acid with a molar concentration of 0.15-0.2mol / L, heated to 80-100°C, pickled for 2-2.5h, solid-liquid separation, washed until neutral, immersed in a magnesium nitrate solution with a molar concentration of 0.6-0.8mol / L, ultrasonicated for 30-40min, solid-liquid separation, washed, dried, sintered at 550-600°C for 1.5-2h, cooled to obtain a magnesium-modified ceramsite carrier.

[0016] Preferably, the mass ratio of the kaolin, the pore-forming agent and the magnesium-modified molecular sieve is (6-6.5):2.5:(1-1.5).

[0017] In this solution, the magnesium-modified ceramsite carrier forms a porous and stable structure through rational ingredient formulation and a step-by-step process. Kaolin and other raw materials undergo sintering to create pores, followed by acid washing and magnesium nitrate impregnation. This not only provides ample loading space for the active particles, but also modulates the surface properties and enhances the bond between the active particles and the carrier. This not only ensures oxygen mass transfer and dispersion of the active components, but also helps create an oxygen vacancy gradient, ultimately synergistically improving the efficiency and lifespan of the deoxidizer.

[0018] Preferably, the preparation method of the magnesium-modified molecular sieve comprises the following steps: The SBA-15 molecular sieve was placed in a sintering furnace, heated to 550-600°C, kept warm for 3.5-4 hours, cooled to room temperature, immersed in nitric acid with a molar concentration of 0.15-0.2 mol / L, heated to 80-100°C, acid-washed for 3-4 hours, solid-liquid separation, washed until neutral, immersed in a magnesium nitrate solution with a molar concentration of 0.6-0.8 mol / L, ultrasonicated for 30-40 minutes, solid-liquid separation, washed, dried, sintered at 550-600°C for 2.5-3 hours, and cooled to obtain a magnesium-modified molecular sieve.

[0019] In this scheme, the magnesium-modified molecular sieve is prepared by high-temperature pretreatment to activate the SBA-15 molecular sieve, followed by nitric acid washing to remove impurities and increase surface active sites. Ultrasonic impregnation with magnesium nitrate achieves uniform magnesium loading, and finally, high-temperature sintering transforms the magnesium into a stable active phase, thereby endowing the molecular sieve with abundant magnesium active sites and suitable surface chemical properties. This process aims to introduce uniformly dispersed magnesium into the ceramsite support, strengthen the interfacial synergy between the support and the deoxidizing active particles, and ultimately, together with the support and active components, promote improved deoxidation performance.

[0020] Preferably, the preparation method of the magnesium-modified ceramsite carrier further includes the step of adding alumina fiber after the magnesium-modified molecular sieve, and the amount of the alumina fiber is 3% to 4% of the total mass of kaolin, pore-forming agent and magnesium-modified molecular sieve.

[0021] In this solution, the compressive strength of the ceramsite carrier is improved by the mechanical reinforcement effect of alumina fiber. In addition, its fibrous structure can be interwoven with the ceramic skeleton to form a network, which inhibits excessive pore collapse during the sintering process and helps maintain the integrity of the porous structure of the carrier.

[0022] Preferably, in step S1, after the nickel salt, a step of adding a strontium salt is further included, and the molar ratio of the lanthanum salt to the strontium salt is 1:(0.1-0.2).

[0023] In this scheme, strontium salt is introduced into the preparation of particle A and the specific molar ratio of lanthanum and strontium is controlled. The doping effect of strontium ions is utilized: the ionic radius of strontium is close to that of lanthanum, and it can partially replace La 3+ A solid solution is formed, which increases the oxygen vacancy concentration through the charge compensation mechanism and further broadens the oxygen migration channel.

[0024] Preferably, in step S3, after particles B, a step of adding nano-strontium titanate is further included, wherein the amount of nano-strontium titanate is 3% to 5% of the total mass of particles A and particles B.

[0025] In this scheme, nano-strontium titanate has a similar structure to particle A, forming a coherent interface and reducing the energy barrier for oxygen ion migration.

[0026] Preferably, the nano-strontium titanate undergoes the following processing steps before use: Nano-strontium titanate and polyvinyl pyrrolidone (PVP) are uniformly mixed in a mass ratio of 1: (1-1.1), anhydrous ethanol is added, ball-milled evenly, dried, and sieved to obtain pretreated nano-strontium titanate.

[0027] In a second aspect, the present application provides a deoxidizer prepared by the above preparation method.

[0028] In summary, this application has the following beneficial effects: This application synthesizes particles A and B in steps. After the two are compounded, the oxygen vacancy concentration gradient generated drives the directional migration of oxygen ions, combines the cycle of surface oxygen activation and lattice oxygen storage, and significantly improves the deoxidation rate and capacity. At the same time, relying on the porous structure of the carrier, the synergistic improvement of deoxidation performance and service life is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the XRD pattern of the deoxidizer in Example 2 of the present application; Figure 2 This is the XRD pattern of the deoxidizer in Comparative Example 1 of this application. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the embodiments.

[0031] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0032] The particle size distribution of nano-strontium titanate is 40~60nm; The particle size distribution of alumina fiber is 5~20μm; Kaolin particle size distribution is 2~5μm; The particle size distribution of SBA-15 molecular sieve is 1~5μm.

[0033] Example 1 The preparation method of the deoxidizer of this embodiment comprises the following steps: S1: 0.1 mol of lanthanum nitrate hexahydrate, 0.08 mol of manganese nitrate tetrahydrate, and 0.02 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.2 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 5.5 with 15% ammonia water, the temperature was raised to 80°C, and the mixture was stirred for 100 min. The mixture was cooled to room temperature and homogenized three times at 150 MPa and 25°C. The mixture was spray-dried with an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace and heated to 300°C at a rate of 5°C / min. The mixture was kept warm for 60 min. The mixture was then switched to a mixed gas of oxygen and nitrogen with a volume ratio of 20:80 at a flow rate of 1.0 L / min. The temperature was continued to rise to 750°C, sintered for 3 h, and cooled to room temperature to obtain particles A. S2: 0.1 mol of cerium nitrate hexahydrate, 0.005 mol of manganese nitrate tetrahydrate, and 0.005 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.11 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 5.5 with 15% ammonia water, the mixture was heated to 80°C, and the mixture was stirred for 100 min. The mixture was cooled to room temperature, homogenized three times at 150 MPa and 25°C, and spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace, heated to 600°C at a rate of 5°C / min, kept at this temperature for 3 h, and cooled to room temperature to obtain particles B. S3: After mixing 20g of particles A and 15g of particles B, place them in a ball mill and grind them for 5h. Then, add 0.53g of polyvinyl pyrrolidone and 85g of deionized water. Transfer them to an ultrasonic device with a power of 500W and a frequency of 40KHz for 30min. Add about 220g of magnesium-modified ceramsite carrier, evacuate to -0.1MPa, vacuum impregnate for 50min, remove the residual liquid on the surface, dry at 80℃ for 3h, transfer to a sintering furnace, and heat to 500℃ at a rate of 2℃ / min under a mixture of hydrogen and nitrogen with a volume ratio of 7:93 at a flow rate of 0.5L / min. Keep warm for 130min and cool to room temperature to obtain a deoxidizer.

[0034] The preparation method of the magnesium-modified ceramsite carrier comprises the following steps: 210 g of kaolin, 87.5 g of corn starch and 52.5 g of magnesium-modified molecular sieve were added to a container, 120 mL of deionized water was added, and the mixture was kneaded evenly. The mixture was extruded using a plum blossom-shaped through-hole die (outer diameter 3 mm / pore diameter 1 mm), and cut into 5 mm cylinders. The mixture was first dried at 80 ° C for 2 h, then heated to 100 ° C, dried for 2 h, and then heated to 120 ° C, dried for 2 h. The mixture was then transferred to a sintering furnace and heated to 550 ° C at a rate of 5 ° C / min, kept warm for 2 h, and switched to a nitrogen atmosphere with a flow rate of 1 L / min. min, continue to heat to 1100 ° C, keep warm for 3 hours, cool to room temperature, immerse in 0.15 mol / L nitric acid solution, heat to 100 ° C, pickle for 2 hours, filter, wash with deionized water until neutral, then immerse in 0.6 mol / L magnesium nitrate solution, ultrasonic for 30 minutes, power 300 W, frequency 40KHz, filter, dry at 100 ° C for 2 hours, transfer to a sintering furnace, heat to 550 ° C at 5 ° C / min, sinter for 2 hours, and cool to room temperature to obtain a magnesium modified ceramsite carrier.

[0035] The preparation method of magnesium-modified molecular sieve comprises the following steps: 100 g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 550°C at 5°C / min, kept warm for 4 hours, cooled to room temperature, immersed in 0.15 mol / L nitric acid solution, heated to 100°C, acid washed for 3 hours, filtered, washed with deionized water until neutral, dried at 80°C for 2 hours, immersed in 0.6 mol / L magnesium nitrate solution, ultrasonicated for 30 minutes with a power of 300 W and a frequency of 20 kHz, filtered, rinsed with deionized water twice, rinsed with anhydrous ethanol once, dried at 100°C for 2 hours, transferred to a sintering furnace, heated to 550°C at 5°C / min, kept warm for 3 hours, and cooled to room temperature to obtain a magnesium-modified molecular sieve.

[0036] Example 2 The preparation method of the deoxidizer of this embodiment comprises the following steps: S1: 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, and 0.05 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the temperature was raised to 75°C, and the mixture was stirred for 120 min. The mixture was cooled to room temperature and homogenized 4 times at 140 MPa and 20°C. The mixture was spray-dried with an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace and heated to 280°C at a rate of 5°C / min. The mixture was kept warm for 70 min. The mixture was then switched to a mixed gas of oxygen and nitrogen with a volume ratio of 15:85 at a flow rate of 1.0 L / min. The temperature was continued to rise to 720°C, sintered for 3.5 h, and cooled to room temperature to obtain particles A. S2: 0.1 mol of cerium nitrate hexahydrate, 0.004 mol of manganese nitrate tetrahydrate, and 0.004 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.16 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the mixture was heated to 75°C, and the mixture was stirred for 120 min. The mixture was cooled to room temperature, homogenized four times at 140 MPa and 20°C, and spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace, heated to 580°C at a rate of 5°C / min, kept at this temperature for 3.5 h, and cooled to room temperature to obtain particles B. S3: After mixing 15g of particles A and 15g of particles B, place them in a ball mill and grind them for 4h. Then, add 0.6g of polyvinyl pyrrolidone and 70g of deionized water. Transfer them to an ultrasonic device with a power of 500W and a frequency of 40KHz for 40min. Add about 150g of magnesium-modified ceramsite carrier, evacuate to -0.1MPa, vacuum impregnate for 45min, remove the residual liquid on the surface, dry at 80℃ for 3h, transfer to a sintering furnace, and heat to 480℃ at a rate of 2℃ / min under a mixture of hydrogen and nitrogen with a volume ratio of 5:95 at a flow rate of 0.5L / min. Keep warm for 150min and cool to room temperature to obtain a deoxidizer.

[0037] The preparation method of the magnesium-modified ceramsite carrier comprises the following steps: 195 g of kaolin, 75 g of corn starch and 30 g of magnesium-modified molecular sieve were added to a container, 105 mL of deionized water was added, and the mixture was kneaded evenly. The mixture was extruded using a plum blossom-shaped through-hole die (outer diameter 3 mm / pore diameter 1 mm), and cut into 5 mm cylinders. The mixture was first dried at 80 ° C for 2 h, then heated to 100 ° C, dried for 2 h, and then heated to 120 ° C, dried for 2 h, and then transferred to a sintering furnace and heated to 600 ° C at 5 ° C / min, kept warm for 1.5 h, and switched to a nitrogen atmosphere with a flow rate of 1 L / min. , continue to heat to 1150℃, keep warm for 2.5h, cool to room temperature, immerse in 0.2mol / L nitric acid solution, heat to 80℃, pickle for 2.5h, filter, wash with deionized water until neutral, then immerse in 0.8mol / L magnesium nitrate solution, ultrasonic for 40min, power 300W, frequency 40KHz, filter, dry at 100℃ for 2h, transfer to a sintering furnace, heat to 600℃ at 5℃ / min, sinter for 1.5h, cool to room temperature to obtain a magnesium-modified ceramsite carrier.

[0038] The preparation method of magnesium-modified molecular sieve comprises the following steps: 100 g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 600 ° C at 5 ° C / min, kept warm for 3.5 hours, cooled to room temperature, immersed in 0.2 mol / L nitric acid solution, heated to 80 ° C, acid washed for 4 hours, filtered, washed with deionized water until neutral, dried at 80 ° C for 2 hours, immersed in 0.8 mol / L magnesium nitrate solution, ultrasonicated for 40 minutes, power 300 W, frequency 20KHz, filtered, rinsed with deionized water twice, rinsed with anhydrous ethanol once, dried at 100 ° C for 2 hours, transferred to a sintering furnace, heated to 600 ° C at 5 ° C / min, kept warm for 2.5 hours, and cooled to room temperature to obtain magnesium modified molecular sieve.

[0039] Example 3 The preparation method of the deoxidizer of this embodiment comprises the following steps: S1: 0.1 mol of lanthanum nitrate hexahydrate, 0.07 mol of manganese nitrate tetrahydrate, and 0.03 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the temperature was raised to 85°C, and the mixture was stirred for 90 min. The mixture was cooled to room temperature, homogenized three times at 160 MPa and 25°C, and spray-dried with an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace and heated to 320°C at a rate of 5°C / min. The mixture was kept warm for 50 min, and then switched to a mixed gas of oxygen and nitrogen with a volume ratio of 20:80 at a flow rate of 1.0 L / min. The temperature was continued to rise to 760°C, sintered for 3 h, and cooled to room temperature to obtain particles A. S2: 0.1 mol of cerium nitrate hexahydrate, 0.006 mol of manganese nitrate tetrahydrate, and 0.004 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.16 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the mixture was heated to 85°C, and the mixture was stirred for 90 min. The mixture was cooled to room temperature, homogenized three times at 160 MPa and 25°C, and spray-dried at an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace, heated to 620°C at a rate of 5°C / min, kept at this temperature for 3 h, and cooled to room temperature to obtain particles B. S3: After mixing 20 g of particle A and 15 g of particle B, place them in a ball mill and grind for 4 hours. Then add 0.88 g of polyvinyl pyrrolidone and 90 g of deionized water, transfer them to an ultrasonic device with a power of 500 W and a frequency of 40 kHz for 35 minutes, add about 210 g of magnesium-modified ceramsite carrier, evacuate to -0.1 MPa, vacuum impregnate for 55 minutes, remove the residual liquid on the surface, dry at 80°C for 3 hours, transfer to a sintering furnace, and heat to 520°C at a rate of 2°C / min under a mixture of hydrogen and nitrogen with a volume ratio of 10:90 at a flow rate of 0.5 L / min. Keep warm for 110 minutes and cool to room temperature to obtain a deoxidizer.

[0040] The preparation method of the magnesium-modified ceramsite carrier comprises the following steps: 195 g of kaolin, 75 g of corn starch, 30 g of magnesium-modified molecular sieves and 9 g of alumina fiber were added to a container, 110 mL of deionized water was added, and the mixture was kneaded evenly. The mixture was extruded using a plum blossom-shaped through-hole die (outer diameter 3 mm / pore diameter 1 mm), and cut into 5 mm cylinders. The mixture was first dried at 80 ° C for 2 h, then heated to 100 ° C, dried for 2 h, and then heated to 120 ° C, dried for 2 h, and then transferred to a sintering furnace and heated to 600 ° C at 5 ° C / min. The mixture was kept warm for 1.5 h, and then switched to a nitrogen atmosphere with a flow rate of 1 L. / min, continue to heat to 1150℃, keep warm for 2.5h, cool to room temperature, immerse in 0.2mol / L nitric acid solution, heat to 80℃, pickle for 2.5h, filter, wash with deionized water until neutral, then immerse in 0.8mol / L magnesium nitrate solution, ultrasonic for 40min, power 300W, frequency 40KHz, filter, dry at 100℃ for 2h, transfer to a sintering furnace, heat to 600℃ at 5℃ / min, sinter for 1.5h, cool to room temperature to obtain a magnesium-modified ceramsite carrier.

[0041] The preparation method of magnesium-modified molecular sieve comprises the following steps: 100 g of SBA-15 molecular sieve was placed in a sintering furnace, heated to 600 ° C at 5 ° C / min, kept warm for 3.5 hours, cooled to room temperature, immersed in 0.2 mol / L nitric acid solution, heated to 80 ° C, acid washed for 4 hours, filtered, washed with deionized water until neutral, dried at 80 ° C for 2 hours, immersed in 0.8 mol / L magnesium nitrate solution, ultrasonicated for 40 minutes, power 300 W, frequency 20KHz, filtered, rinsed with deionized water twice, rinsed with anhydrous ethanol once, dried at 100 ° C for 2 hours, transferred to a sintering furnace, heated to 600 ° C at 5 ° C / min, kept warm for 2.5 hours, and cooled to room temperature to obtain magnesium modified molecular sieve.

[0042] Example 4 The difference between this embodiment and embodiment 3 is that: In step S1, 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, 0.05 mol of nickel nitrate hexahydrate, and 0.01 mol of strontium nitrate were dissolved in 500 mL of deionized water, 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, and the mixture was heated to 85 ° C. and continued to be stirred for 90 min. The mixture was cooled to room temperature, homogenized 3 times at 160 MPa and 25 ° C., spray dried with an inlet temperature of 180 ° C. and an outlet temperature of 80 ° C., and then transferred to a sintering furnace, heated to 320 ° C. at 5 ° C. / min, and kept warm for 50 min. Then, a mixed gas of oxygen and nitrogen with a volume ratio of 20:80 was switched at a flow rate of 1.0 L / min, and the temperature was continued to rise to 760 ° C., sintered for 3 h, and cooled to room temperature to obtain particles A. The preparation method of the magnesium-modified ceramsite carrier comprises the following steps: 195 g of kaolin, 75 g of corn starch, 30 g of magnesium-modified molecular sieves and 12 g of alumina fiber were added to a container, 110 mL of deionized water was added, and the mixture was kneaded evenly. The mixture was extruded using a plum blossom-shaped through-hole die (outer diameter 3 mm / pore diameter 1 mm), and cut into 5 mm cylinders. The mixture was first dried at 80 ° C for 2 h, then heated to 100 ° C, dried for 2 h, and then heated to 120 ° C, dried for 2 h. The mixture was then transferred to a sintering furnace and heated to 600 ° C at a rate of 5 ° C / min, kept warm for 1.5 h, and switched to a nitrogen atmosphere with a flow rate of 1 L / min, continue to heat to 1150℃, keep warm for 2.5h, cool to room temperature, immerse in 0.2mol / L nitric acid solution, heat to 80℃, pickle for 2.5h, filter, wash with deionized water until neutral, then immerse in 0.8mol / L magnesium nitrate solution, ultrasonic for 40min, power 300W, frequency 40KHz, filter, dry at 100℃ for 2h, transfer to a sintering furnace, heat to 600℃ at 5℃ / min, sinter for 1.5h, cool to room temperature to obtain a magnesium-modified ceramsite carrier.

[0043] Other details are the same as in Example 3.

[0044] Example 5 The difference between this embodiment and embodiment 4 is that: In step S3, after particles B, 1.05 g of nano-strontium titanate is also added.

[0045] Among them, nano strontium titanate undergoes the following processing steps before use: Nano-strontium titanate and polyvinyl pyrrolidone (PVP) were mixed in a mass ratio of 1:1, anhydrous ethanol was added, and the solid-liquid ratio was 1:5. The mixture was ball-milled for 2 h, dried at 60°C to constant weight, and passed through a 300-mesh sieve. The sieve was taken and set aside.

[0046] Other details are the same as in Example 4.

[0047] Example 6 The difference between this embodiment and embodiment 5 is that: In step S1, 0.1 mol of lanthanum nitrate hexahydrate, 0.05 mol of manganese nitrate tetrahydrate, 0.05 mol of nickel nitrate hexahydrate, and 0.02 mol of strontium nitrate were dissolved in 500 mL of deionized water, 0.3 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the mixture was heated to 85 ° C, and the mixture was stirred for 90 min. The mixture was cooled to room temperature, homogenized 3 times at 160 MPa and 25 ° C, spray dried with an inlet temperature of 180 ° C and an outlet temperature of 80 ° C, and then transferred to a sintering furnace, heated to 320 ° C at 5 ° C / min, and kept warm for 50 min. Then, a mixed gas of oxygen and nitrogen with a volume ratio of 20:80 was switched at a flow rate of 1.0 L / min, and the temperature was continued to rise to 760 ° C, sintered for 3 h, and cooled to room temperature to obtain particles A; In step S3, after particles B, 1.75 g of nano-strontium titanate is also added.

[0048] Among them, nano strontium titanate undergoes the following processing steps before use: Nano-strontium titanate and polyvinyl pyrrolidone (PVP) were mixed at a mass ratio of 1:1.1, anhydrous ethanol was added, and the solid-liquid ratio was 1:5. The mixture was ball-milled for 2 h, dried at 60°C to constant weight, and passed through a 300-mesh sieve. The sieve was taken and set aside.

[0049] Other details are the same as in Example 5.

[0050] Comparative Example 1 The preparation method of the deoxidizer of this comparative example comprises the following steps: S1: 0.1 mol of lanthanum nitrate hexahydrate, 0.1 mol of cerium nitrate hexahydrate, 0.054 mol of manganese nitrate tetrahydrate, and 0.054 mol of nickel nitrate hexahydrate were dissolved in 1000 mL of deionized water, 0.46 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 6.0 with 15% ammonia water, the temperature was raised to 75°C, and the mixture was stirred for 120 min. The mixture was cooled to room temperature and homogenized four times at 140 MPa and 20°C. The mixture was spray-dried with an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace and heated to 280°C at a rate of 5°C / min. The mixture was kept warm for 70 min. The mixture was then switched to a mixture of oxygen and nitrogen with a volume ratio of 15:85 at a flow rate of 1.0 L / min. The temperature was continued to rise to 720°C, sintered for 3.5 h, and cooled to room temperature to obtain particles. S2: Place 30g of the particles in a ball mill and grind for 4h, add 0.6g of polyvinyl pyrrolidone and 70g of deionized water, transfer to an ultrasonic device with a power of 500W and a frequency of 40KHz for 40min, add about 150g of a magnesium-modified ceramsite carrier, evacuate to -0.1MPa, vacuum impregnate for 45min, remove the residual liquid on the surface, dry at 80℃ for 3h, transfer to a sintering furnace, and heat to 480℃ at a flow rate of 0.5L / min in a mixture of hydrogen and nitrogen with a volume ratio of 5:95, keep warm for 150min, and cool to room temperature to obtain a deoxidizer.

[0051] Other details are the same as in Example 2.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is: The preparation method of the ceramsite carrier comprises the following steps: 210 g of kaolin, 87.5 g of corn starch and 52.5 g of magnesium-modified molecular sieve were added to a container, 120 mL of deionized water was added, and the mixture was kneaded evenly. The mixture was extruded using a plum blossom-shaped through-hole die (outer diameter 3 mm / pore diameter 1 mm), cut into 5 mm cylinders, dried at 80 ° C for 2 h, then heated to 100 ° C, dried for 2 h, continued to heat to 120 ° C, dried for 2 h, and then transferred to a sintering furnace, heated to 550 ° C at 5 ° C / min, kept warm for 2 h, switched to a nitrogen atmosphere with a flow rate of 1 L / min, continued to heat to 1100 ° C, kept warm for 3 h, cooled to room temperature, immersed in 0.15 mol / L nitric acid solution, heated to 100 ° C, acid washed for 2 h, filtered, washed with deionized water until neutral, and dried to constant weight at 100 ° C to obtain a ceramsite carrier.

[0053] Other details are the same as in Example 1.

[0054] Comparative Example 3 The difference between this comparative example and Example 1 is: The preparation method of the deoxidizer of this comparative example comprises the following steps: S1: 0.1 mol of lanthanum nitrate hexahydrate, 0.08 mol of manganese nitrate tetrahydrate, and 0.02 mol of nickel nitrate hexahydrate were dissolved in 500 mL of deionized water, 0.2 mol of citric acid was added, and the mixture was stirred at 200 rpm for 30 min. The pH was adjusted to 5.5 with 15% ammonia water, the temperature was raised to 80°C, and the mixture was stirred for 100 min. The mixture was cooled to room temperature, homogenized three times at 150 MPa and 25°C, and spray-dried with an inlet temperature of 180°C and an outlet temperature of 80°C. The mixture was then transferred to a sintering furnace and heated to 300°C at a rate of 5°C / min. The mixture was kept warm for 60 min, and then switched to a mixed gas of oxygen and nitrogen with a volume ratio of 20:80 at a flow rate of 1.0 L / min. The temperature was continued to rise to 750°C, sintered for 3 h, and cooled to room temperature to obtain particles. S3: 20 g of particles were placed in a ball mill and ground for 5 h. 0.4 g of polyvinyl pyrrolidone and 45 g of deionized water were added. The particles were transferred to an ultrasonic device with a power of 500 W and a frequency of 40 KHz for 30 min. About 120 g of magnesium-modified ceramsite carrier was added. The particles were evacuated to -0.1 MPa and vacuum impregnated for 50 min. The residual liquid on the surface was removed. The particles were dried at 80 ° C for 3 h and transferred to a sintering furnace. The mixture was heated to 500 ° C at a rate of 2 ° C / min under a mixture of hydrogen and nitrogen with a volume ratio of 7:93 and a flow rate of 0.5 L / min. The mixture was kept warm for 130 min and cooled to room temperature to obtain a deoxidizer.

[0055] Other details are the same as in Example 1.

[0056] Performance testing The deoxidizers prepared in Examples 1 to 6 and Comparative Examples 1 to 3 were respectively loaded into a fixed bed reactor (loading amount was 50 g), the operating temperature was set to 25±5°C, the pressure was set to 5 MPa, propylene gas with an oxygen content of 100 ppm was introduced, and the space velocity was set to 1000 h -1 The oxygen concentration of the outlet gas was monitored with an online laser oxygen analyzer. When the outlet oxygen concentration was ≤0.1ppm, it was judged to be qualified. The gas was ventilated continuously until the outlet oxygen concentration was ≥0.1ppm, then the test was stopped, the cumulative volume of oxygen adsorbed by the deoxidizer was recorded, and the deoxidation capacity (unit: mL / g) was calculated. After each failure, it was regenerated for 2h in a mixed atmosphere of H2 and N2 (volume ratio of 10:90) at 500℃. After the activity was restored, the above deoxidation test was repeated. After 50 cycles, the capacity retention rate was calculated (capacity after cycle / initial capacity×100%). Five molded deoxidizer particles were randomly selected, the surface dust was cleaned with anhydrous ethanol, and the particles were dried at 60℃. The maximum pressure when a single particle was broken was measured, and the average value was taken. The specific results are shown in Table 1.

[0057] Table 1 Performance test data of deoxidizers prepared in Examples 1 to 6 and Comparative Examples 1 to 3

[0058] The comparison of the performance data of Examples 1 to 3 and Comparative Examples 1 to 3 shows that the step-by-step synthesis process of the present application is the key to improving the deoxidation performance: Examples 1 to 3 construct a multiphase composite system of perovskite phase (auxiliary phase: metal Ni phase), fluorite phase CeO2 and magnesium modified carrier through a step-by-step synthesis process. The key is that this process effectively isolates different precursors, ensures the independent formation and coexistence of key functional phases (especially the efficient oxygen storage phase CeO2), and forms a synergistic interface between the multiphases (especially the perovskite phase / fluorite phase CeO2 interface), realizing the functional coupling and kinetic acceleration of oxygen storage-oxygen transfer-oxygen consumption, which is the core mechanism for the significant improvement of deoxidation capacity. In contrast, the one-step process of Comparative Example 1 is due to CeO2. 4+The deoxidizer exhibits poor structural compatibility with perovskite, resulting in a phase-separated mixture of defective perovskite and CeO2. Subsequent reduction treatment further induces the precipitation of nickel ions into a metallic nickel phase, resulting in a deoxidation capacity far lower than that of a multiphase system synthesized in a step-by-step manner. Furthermore, the optimized sintering of the alumina fiber reinforcement and magnesium-modified support significantly enhances the deoxidizer's mechanical strength and structural stability, providing a solid physical foundation for maintaining high activity during long-term cycling.

[0059] According to Example 4, Sr 2+ La is doped and the charge imbalance effect is used to induce lattice oxygen vacancies, thereby improving the oxygen ion mobility; Examples 5-6 introduce nano-strontium titanate, which forms a coherent interface with the main perovskite phase. The interface lattice distortion reduces the oxygen migration energy barrier, thereby achieving accelerated deoxygenation kinetics and improved cycle stability.

[0060] Combine Figure 1 As can be seen, Example 2 utilizes a distributed synthesis process: in step S1, a pure La(Mn,Ni)O3 perovskite phase is formed, exhibiting characteristic peaks at 32.5°, 40°, and 46°; in step S2, a Mn and Ni-doped CeO2 fluorite phase is formed, corresponding to characteristic peaks at 28.5°, 47.5°, and 56.3°. The magnesium modification process introduces a MgO phase, corresponding to a characteristic peak at 42.9°. The reduction treatment does not disrupt the host lattice, and no characteristic peak of metallic nickel appears. The characteristic peak at 30.5° indicates that lattice strain and electronic interaction occur between the two active phases at the interface, forming an oxygen vacancy migration channel. The coexistence of the multiphase characteristic peaks (perovskite, fluorite, and support) precisely separated by XRD and the interface peak confirms that the step-by-step synthesis process successfully constructs a multiphase synergistic structure, with nickel and manganese ions stably dissolved in the lattice and reduction only optimizing surface valence states and oxygen vacancies.

[0061] Combine Figure 2 It can be seen that Comparative Example 1 adopts the co-precipitation one-pot method to form a single (La, Ce)(Mn, Ni)O3 solid solution, but due to Ce 4+ Incompatible with the perovskite structure, sintering actually produces defective perovskite phases (33°, 40.3°) and isolated CeO₂ phases (28.5°, 47.5°). Subsequent reduction treatment causes nickel ions to escape the unstable lattice, precipitating metallic nickel (characteristic peak at 43.2°), while the support contributes a MgO peak (42.9°). The 47.3° peak in the XRD pattern represents an overlap of CeO₂ and perovskite, while the interfacial coupling peak (30.5°) is missing. This suggests that the coprecipitation process induces cerium phase separation, and the reduction step destroys the perovskite structure, resulting in a multiphase mixture of the final product, which is inconsistent with the target solid solution design.

[0062] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing a deoxidizer, characterized in that: The steps include: S1: Dissolve lanthanum salt, manganese salt, and nickel salt in a molar ratio of 1:x:(1-x) in water, add citric acid, adjust the pH to 5.5-6.0, heat to 75-85°C, mix for 90-120 minutes, spray dry, first heat at 280-320°C, keep warm for 50-70 minutes, switch to a mixture of O2 and N2, and sinter at 720-760°C for 3-3.5 hours to obtain particles A; S2: Dissolve cerium salt, manganese salt, and nickel salt in a molar ratio of 1:(0.04-0.06):(0.04-0.05) in water, add citric acid, adjust the pH to 5.5-6.0, heat to 75-85°C, mix for 90-120 minutes, spray dry, and sinter at 580-620°C for 3-3.5 hours to obtain particles B; S3: Mix particles A and B, grind for 4-5 hours, add dispersant and water, mix evenly, add magnesium-modified ceramsite carrier, vacuum impregnate for 45-55 minutes, separate the solid and liquid, dry, keep warm at 480-520°C for 110-150 minutes under a mixture of H2 and N2, cool, and obtain a deoxidizer.

2. The method for preparing a deoxidizer according to claim 1, wherein In step S3, the mass ratio of particles A to particles B is (3-4):

3.

3. The method for preparing a deoxidizer according to claim 1, wherein In step S1, the value range of x is 0.5~0.

8.

4. The method for preparing a deoxidizer according to claim 1, wherein In step S3, in the mixture of H2 and N2, the volume ratio of H2 to N2 is (5-10): (90-95).

5. The method for preparing a deoxidizer according to claim 1, wherein The preparation method of the magnesium-modified ceramsite carrier comprises the following steps: The kaolin, pore-forming agent and magnesium-modified molecular sieve are added into a reactor, water is added and kneaded evenly, extruded, granulated and dried, first sintered at 550-600°C for 1.5-2h, switched to an inert atmosphere, continued to heat up to 1100-1150°C, sintered for 2.5-3h, cooled, immersed in nitric acid with a molar concentration of 0.15-0.2mol / L, heated to 80-100°C, pickled for 2-2.5h, solid-liquid separation, washed until neutral, immersed in a magnesium nitrate solution with a molar concentration of 0.6-0.8mol / L, ultrasonicated for 30-40min, solid-liquid separation, washed, dried, sintered at 550-600°C for 1.5-2h, cooled to obtain a magnesium-modified ceramsite carrier.

6. The method for preparing the deoxidizer according to claim 5, wherein The mass ratio of the kaolin, the pore-forming agent and the magnesium-modified molecular sieve is (6-6.5):2.5:(1-1.5).

7. The method for preparing a deoxidizer according to claim 5, wherein: The preparation method of the magnesium-modified molecular sieve comprises the following steps: The SBA-15 molecular sieve was placed in a sintering furnace, heated to 550-600°C, kept warm for 3.5-4 hours, cooled to room temperature, immersed in nitric acid with a molar concentration of 0.15-0.2 mol / L, heated to 80-100°C, acid-washed for 3-4 hours, solid-liquid separation, washed until neutral, immersed in a magnesium nitrate solution with a molar concentration of 0.6-0.8 mol / L, ultrasonicated for 30-40 minutes, solid-liquid separation, washed, dried, sintered at 550-600°C for 2.5-3 hours, and cooled to obtain a magnesium-modified molecular sieve.

8. The method for preparing a deoxidizer according to claim 5, wherein The preparation method of the magnesium-modified ceramsite carrier further includes the step of adding alumina fiber after the magnesium-modified molecular sieve, wherein the amount of the alumina fiber is 3% to 4% of the total mass of kaolin, pore-forming agent and magnesium-modified molecular sieve.

9. The method for preparing a deoxidizer according to claim 1, wherein In step S1, after the nickel salt, a strontium salt is further added, and the molar ratio of the lanthanum salt to the strontium salt is 1:(0.1-0.2).

10. A deoxidizer prepared by the method for preparing a deoxidizer according to any one of claims 1 to 9.

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